Automatic headlight dimmer



Mardi 6, 1956 H. A. GOLDSMITH ETAL 2,737,599

AUTOMATIC HEADLIGHT DIMMER Filed Aug. 24, 1954 United States Patent O 2,737 ,599 AUTOMATIC HEADLIGHT DIMMER Harold A. Goldsmith, Elmhurst, Herbert Herz, Forest Hills, and Arthur Z. Gutterman, New Rochelle, N. Y., assiguors to Magnetic Amplifiers, Inc., a corporation of New York Application August 24, 1954, Serial No. 451,766 3 Claims. (Cl. 307-41) This invention relates to a device for automatically dimming headlights of an automobile upon the approach of another automobile.

Among the objects of the invention is to provide a device which acts automatically to dim the headlights of an automobile or shift from a high to a low beam when another automobile approaches within a certain distance.

All automobiles are provided with manually operated dimming devices but often the driver forgets to dim the light when another car approaches and often the driver does not know whether he is using the dim or the undim lights for driving.

There are a number of electronic and electric circuits available which are sensitive to light of a certain intensity which may be employed as an automatic dimmer but for the most part, at least, such known circuits are bulky, unreliable, and/or expensive. In this speciication the expression to dim the lights will be understood to cover either a dimming or a shifting from high beam to low beam.

Among other objects of this invention is to provide a simple, inexpensive, rugged and reliable device for automatically dimming the headlights of an automobile.

These and other objects ancillary thereto are obtained by combining a photosensitive device in a circuit with a low voltage magnetic amplifier and a relay which conlight dimmer switch. The circuit is energized sides except the side directed toward the approaching automobiles. When little or no light strikes the photosensitive device, this device acts as a good rectifier and presaturates the magnetic core of the magnetic amplifier. When the magnetic core is the power is transferred almost entirely to the which is therefore in the energized state. of suficient intensity strikes it becomes a poor rectifier and passes more alternating current.

cell, a photo-transistor, etc.

In the drawing, the figure shows a diagrammatic circuit for the device of the invention.

The automobile battery which may be of 6 or 24 The terminal 13 is connected to one side of the photosensitive device 15. The other side of the photosensitive device 15 is connected to one terminal of the two terminal magnetic amplifier 16. The other terminal of the magnetic amplifier 16 is connected to relay 17. The order of connecting the magnetic amplifier 16, photosensitive device 15 and relay 17 can be changed.

The relay 17 closes the circuit between line 21 and either line 22 or line 23. In the device shown terminal 18 and line 23 operate the bright light filament of the automobile headlight bulbs and terminal 19 and line 22 operate the dimming filaments of the headlight bulbs.

In operation, substantially the entire circuit including the magnetic amplifier, the relay, the vibrator and sensitive device 15, conductor of alternating current whereupon relay 17 is deenergized and the dim lights switched on. When the approaching car passes, the relay is again energized and the bright lights again switched on.

It will be seen that the circuit avoids all use of photomultiplier tubes or other vacuum tubes. Photomultiplier tubes require high voltages that may be dangerous device of this inventi n is entirely The magnetic amplifier provides a very rugged and reliable means for controlling the circuit. The device of the inventor requires practically no mainte- Since no vacuum tubes are employed the device by shock normally encountered roads. The vibrator device re on the battery, and the entire device is capable of being packaged in one small unit which requires no installation of accessories under the hood.

ture or details thereof.

I claim:

l. In a device for the automatic dimming of bright and dim type headlights thereon and adapted to operate as a times, whereby said photosensitive device normally acts as rectitier to saturate the magnetic amplifier and energize the relay to complete said second bright light circuit, said photosensitive device being transposed to a conductorwhen light of acertain minimum intensity from the headlights of an approaching vehicle'impinges thereon whereupon the relay is deenergized to complete said first circuit of the dim lights.

e 2. The device as set forth in claim 1 in which the magnetic amplier has only one coil, one core and tWo terminals.

3. The device as set forth in claim 1 in which the l means for supplying alternating current is a vibrator device.

References Cited in the tile of this patent UNITED STATES PATENTS 1,618,816 Davis Feb. 22, 1927 1,878,010 Spahr Sept. 20, 1932 2,067,143 Logan Ian. 5, 1937 10 2,341,526 Breitenstein Feb. 15, 1944 

